The need for precision positioning arises in a wide variety of arts, and many different devices have been devised to satisfy that need. Such devices are generically referred to as positioning stages.
Positioning stages are typically operable to move along one or two or three or more axes. Horizontal one- or two-axes positioning stages are relatively easy to implement, although the art is replete with relatively complicated implementations of such X-Y stages that include elements such as position sensors and linear motors as drive devices.
Vertical (Z-axis) positioning stages are more difficult to implement than horizontal (X-Y) positioning stages. Unlike X-, Y- or XY-stages, a Z-axis positioning stage is not supported in the horizontal plane and therefore requires stabilization in that plane, as well as along the Z-axis. Typically, rails, guide pins, scissors systems or the like are required to maintain the X-Y position of a vertical positioning stage. Moreover, for Z-axis positioning, the weight of the stage and frictional forces associated with the stage's movement must be overcome.
Z-axis positioning stages become especially complicated when rapid stage movement is required. The art has addressed such complications with electrically-driven systems incorporating ball screws, belts and the like, as well as with pneumatically-driven systems. Electrically-driven systems are very complex and require numerous components, and pneumatically-driven systems tend to be very bulky. Both electrical and pneumatic systems typically require special structural frames and supports. Due to their complexity, such systems are relatively expensive and may suffer from reliability problems.
The art would therefore benefit from a simple z-axis positioning stage capable of rapid, precise positioning. Such a stage would be more reliable and less expensive than conventional z-axis positioning stages.